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Sling angle calculator: tension per leg and sling WLL

Tension in each leg of a 1 to 4-leg sling from load and angle, and the sling WLL with the mode factor of EN 818-4, EN 13414-1 and EN 1492-1. Free.

  • Instant result
  • Formula and standards shown
  • On desktop and phone

Pre-filled example

A 2,000 kg load lifted with a two-leg chain sling at 45° from the vertical, each leg rated at 2.5 t WLL.

kg
°
t
More options (1)

Result

13,869NTension per leg

Sling WLL 3.50 t (2 legs, β 45°)

Equivalent mass
1,414.2kg
Mode factor M
1.4
Sling WLL
3.50 t
Load within WLL
Yes
  • Caution : Centre of gravity under the hook and legs of equal length are assumed.
Attach this calculation to a work order

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Does not replace the marked WLL or the manufacturer's value.

Sling angle and WLL noted on the lifting work order

Here, the calculator is free and the result is gone when you close the page. In Reglova, it is attached to the work order on the right machine: you find it again at the next breakdown, and on audit day.

The CMMS software comparison, our gaps included
  • Attached to the work order with its inputs: the server recalculates it, it stays verifiable.
  • On the technician's phone, even without a network.
  • In the machine's history, for the next breakdown.
  • The result becomes a checklist step of the work order.
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Reglova · Calculations · Work order WO-AT01-04219
Silent video, 33 s: from the work order for an oil leak on a shear cylinder, the tightening torque of an M12 bolt, then "Attach to the work order". A step to tighten it to 93.1 N·m lands in the checklist (step text from the French demo data). Watch the video

When to check a sling angle before a lift

  1. 01

    Prepare the lift of a motor or a gearbox with an overhead crane.

  2. 02

    Check that a two-leg sling is suitable at a 45° angle.

  3. 03

    Remind on the work order that a leg must not exceed 60° from the vertical.

Good to know

The calculation assumes the centre of gravity under the hook and legs of equal length. A rigid load on four legs in practice rests on two: count two load-bearing legs.

Leg tension formula and mode factor M

The further the legs spread from the vertical, the higher the tension in each one. The calculator gives the tension per leg from the mass, the number of legs and their angle, then the sling's working load limit with the mode factor M from EN 818-4, EN 13414-1 and EN 1492-1, and says whether the load stays below it.

Formula · Reference documents

T = m·g/(n·cos β) ; WLL = leg WLL × M

EN 818-4 ; EN 13414-1 ; EN 1492-1

Inputs and accepted ranges
InputUnitAccepted rangeExample
Load masskg0.1 to 500,0002,000 kg
Number of legs1 to 42
Leg angle β, from vertical°0 to 6045 °
Hitch3 optionsStraight
Sling type3 optionsChain, EN 818-4
Load-bearing legs1 to 4Optional
Leg WLLt0.01 to 1,0002.5 t
Calculated results
  • Tension per legN
  • Equivalent masskg
  • Mode factor M
  • Sling WLLt
  • Load within WLL
What the calculator flags
  • Centre of gravity under the hook and legs of equal length are assumed.
  • Rigid load on 4 legs: count only 2 load-bearing legs.
  • The load exceeds the sling WLL.

Lifting gear inspections reminded before they lapse

  • Breakdowns reported by QR code
  • Work orders on the phone, even without a network
  • Mandatory inspections reminded by email
  • Audit file as a PDF, in one click
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